The present invention relates to the production of two valuable commodities, elemental chlorine and sulfate salts, from more abundant chloride salts and sulfuric acid. More specifically, it is a process which can be conducted with an energy input primarily of heat energy instead of electrical energy.
Presently, the method of choice for obtaining chlorine from a chloride salt requires electrolysis of the salt in an aqueous solution. This process requires extensive amounts of scarce electrical energy. To operate in an energy-efficient manner, it is thus necessary that an electrolysis plant be located adjacent to a source of low cost electrical energy. But, it is unusual to find existing sources of electrical energy near a source of raw chloride salts, Therefore, to establish a new electrolysis plant, it is usually necessary to construct the plant near an existing source of electrical energy and to expend substantial amounts of energy to transport the chloride salts to the plant or to make a substantial capital and energy investment in new electrical generation capacity and/or new transmission lines to make sufficient low cost electrical energy available to an electrolysis plant constructed near the site where the chloride salts are to be obtained.
Furthermore, the conversion of thermal energy to electrical energy for use in an electrolysis process involves a substantial loss in usable energy. This loss is further magnified if long distance transmission lines are required.
Also, electrolysis processes cannot be used unless the raw material chloride salt is of high purity. Most naturally-occurring salts thus require purification treatments before they can be used in a conventional electrolysis process.
There is a limited number of input raw materials suitable for use in an electrolysis process; and the by-products which result from certain electrolyzed input materials are difficult to market or to dispose of in an environmentally sound manner.